Systems and methods for navigation and control of an implant positioning device

ABSTRACT

Systems and methods for navigation and control of an implant positioning device are discussed. For example, a method can include operations for accessing an implant plan, establishing a 3-D coordinate system, receiving tracking information, generating control signals, and sending the control signals to the implant positioning device. The implant plan can include location and orientation data describing an ideal implant location and orientation in reference to an implant host. The 3-D coordinate system can provide spatial orientation for the implant positioning device and the implant host. The tracking information can identify current location and orientation data within the 3-D coordinate system for the implant positioning device and implant host during a procedure. The control signals can control operation of the implant positioning device to assist a surgeon in positioning the implant according to the implant plan.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/724,601, titled “Systems and Method for Navigation and Control of anImplant Positioning Device,” filed Nov. 9, 2012, which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

This application relates generally to semi-active surgical robotics, andmore specifically to systems and methods to provide computer-aidednavigation and control of an implant positioning device.

BACKGROUND

The use of computers, robotics, and imaging to aid orthopedic surgery iswell known in the art. There has been a great deal of study anddevelopment of computer-aided navigation and robotics systems used toguide surgical procedures. Two general types of semi-active surgicalrobotics have emerged and have been applied to orthopedic procedures,such as joint arthroplasty. The first type of semi-active roboticsattach the surgical tool to a robotic arm that resists movements by thesurgeon that deviate from a planned procedure, such as a bone resection.This first type often goes by the term haptic or haptics, which isderived from the Greek word for touch. The second type of semi-activerobotics is focused on controlling aspects of the surgical tool, such asspeed of a cutting bit. This second type of semi-active robotics issometimes referred to as free-hand robotics, as a robotic arm does notrestrict the surgeon.

Both types of surgical robotics utilize navigation or tracking systemsto closely monitor the surgical tool and the patient during a procedure.The navigation system can be used to establish a virtual threedimensional (3-D) coordinate system, within which both the patient andthe surgical device will be tracked.

Hip replacement is an area where the use of surgical robotics, advancedimaging, and computer-aided navigation are gaining acceptance. Total hipreplacement (THR) or arthroplasty (THA) operations have been performedsince the early 1960s to repair the acetabulum and the regionsurrounding it and to replace the hip components, such as the femoralhead, that have degenerated. Currently, approximately 200,000 THRoperations are performed annually in the United States alone, of whichapproximately 40,000 are redo procedures, otherwise known as revisions.The revisions become necessary due to a number of problems that mayarise during the lifetime of the implanted components, such asdislocation, component wear and degradation, and loosening of theimplant from the bone.

Dislocation of the femoral head from the acetabular component, or cup,is considered one of the most frequent early problems associated withTHR, because of the sudden physical and emotional hardship brought on bythe dislocation. The incidence of dislocation following the primary THRsurgery is approximately 2-6% and the percentage is even higher forrevisions. While dislocations can result from a variety of causes, suchas soft tissue laxity and loosening of the implant, the most commoncause is impingement of the femoral neck with either the rim of anacetabular cup implant, or the soft tissue or bone surrounding theimplant. Impingement most frequently occurs as a result ofmis-positioning of the acetabular cup component within the pelvis.

Some clinicians and researchers have found incidence of impingement anddislocations can be lessened if the cup is oriented specifically toprovide for approximately 15° of anteversion and 45° of abduction;however, this incidence is also related to the surgical approach. Forexample, McCollum et al. cited a comparison of THAs reported in theorthopaedic literature that revealed a much higher incidence ofdislocation in patients who had THAs with a posterolateral approach.McCollum, D. E. and W. J. Gray, “Dislocation after total hiparthroplasty (causes and prevention)”, Clinical Orthopaedics and RelatedResearch, Vol. 261, p. 159-170 (1990). McCollum's data showed that whenthe patient is placed in the lateral position for a posterolateral THAapproach, the lumbar lordotic curve is flattened and the pelvis may beflexed as much as 35°. If the cup was oriented at 15°-20° of flexionwith respect to the longitudinal axis of the body, when the patientstood up and the postoperative lumbar lordosis was regained, the cupcould be retroverted as much as 10°-15° resulting in an unstable cupplacement. Lewinnek et al. performed a study taking into account thesurgical approach utilized and found that the cases falling in the zoneof 15°±10° of anteversion and 40°±10° of abduction have an instabilityrate of 1.5%, compared with a 6% instability rate for the cases fallingoutside this zone. Lewinnek G. E., et al., “Dislocation after totalhip-replacement arthroplasties”, Journal of Bone and Joint Surgery, Vol.60-A, No. 2, p. 217-220 (March 1978). The Lewinnek work essentiallyverifies that dislocations can be correlated with the extent ofmalpositioning, as would be expected. The study does not address othervariables, such as implant design and the anatomy of the individual,both of which are known to greatly affect the performance of theimplant.

The design of the implant significantly affects stability as well. Anumber of researchers have found that the head-to-neck ratio of thefemoral component is the key factor of the implant impingement, seeAmstutz H. C., et al., “Range of Motion Studies for Total HipReplacements”, Clinical Orthopaedics and Related Research Vol. 111, p.124-130 (September 1975). Krushell et al. additionally found thatcertain long and extra long neck designs of modular implants can have anadverse effect on the range of motion. Krushell, R. J., Burke D. W., andHarris W. H., “Range of motion in contemporary total hip arthroplasty(the impact of modular head-neck components)”, The Journal ofArthroplasty, Vol. 6, p. 97-101 (February 1991). Krushell et al. alsofound that an optimally oriented elevated-rim liner in an acetabular cupimplant may improve the joint stability with respect to implantimpingement. Krushell, R. J., Burke D. W., and Harris W. H.,“Elevated-rim acetabular components: Effect on range of motion andstability in total hip arthroplasty”, The Journal of Arthroplasty, Vol.6 Supplement, p. 1-6, (October 1991). Cobb et al. have shown astatistically significant reduction of dislocations in the case ofelevated-rim liners, compared to standard liners. Cobb T. K., Morrey B.F., Ilstrup D. M., “The elevated-rim acetabular liner in total hiparthroplasty: Relationship to postoperative dislocation”, Journal ofBone and Joint Surgery, Vol 78-A, No. 1, p. 80-86, (January 1996). Thetwo-year probability of dislocation was 2.19% for the elevated liner,compared with 3.85% for standard liner. Initial studies by Maxian et al.using a finite element model indicate that the contact stresses andtherefore the polyethylene wear are not significantly increased forelevated rim liners; however, points of impingement and subsequentangles of dislocation for different liner designs are different, aswould be expected. Maxian T. A., et al. “Femoral head containment intotal hip arthroplasty: Standard vs. extended lip liners”, 42nd Annualmeeting, Orthopaedic Research society, p. 420, Atlanta, Ga. (Feb. 19-22,1996); and Maxian T. A., et al. “Finite element modeling of dislocationpropensity in total hip arthroplasty”, 42nd Annual meeting, OrthopaedicResearch society, p. 259-64, Atlanta, Ga. (Feb. 19-22, 1996).

An equally important concern in evaluating the dislocation propensity ofan implant is variations in individual anatomies. As a result ofanatomical variations, there is no single optimal design and orientationof hip replacement components and surgical procedure to minimize thedislocation propensity of the implant. For example, the pelvis canassume different positions and orientations depending on whether anindividual is lying supine (as during a CT-scan or routine X-rays), inthe lateral decubitis position (as during surgery) or in criticalpositions during activities of normal daily living (like bending over totie shoes or during normal gait). The relative position of the pelvisand leg when defining a “neutral” plane from which the angles ofmovement, anteversion, abduction, etc., are calculated willsignificantly influence the measured amount of motion permitted beforeimpingement and dislocation occurs. Therefore, it is necessary touniquely define both the neutral orientation of the femur relative tothe pelvis for relevant positions and activities, and the relationshipof the femur with respect to the pelvis of the patient during eachsegment of leg motion.

Currently, most planning for acetabular implant placement and sizeselection is performed using acetate templates and a singleanterior-posterior x-ray of the pelvis. Acetabular templating is mostuseful for determining the approximate size of the acetabular component;however, it is only of limited utility for positioning of the implantbecause the x-rays provide only a two dimensional image of the pelvis.Also, the variations in pelvic orientation cannot be more fullyconsidered as discussed above.

Intra-operative positioning devices currently used by surgeons attemptto align the acetabular component with respect to the sagittal andcoronal planes of the patient. B. F. Money, editor, “ReconstructiveSurgery of the Joints”, chapter Joint Replacement Arthroplasty, pages605-608, Churchill Livingston, 1996. These devices assume that thepatient's pelvis and trunk are aligned in a known orientation, and donot take into account individual variations in a patient's anatomy orpelvic position on the operating room table. These types of positionerscan lead to a wide discrepancy between the desired and actual implantplacement, possibly resulting in reduced range of motion, impingementand subsequent dislocation.

Several attempts have been made to more precisely prepare the acetabularregion for the implant components. U.S. Pat. No. 5,007,936 issued toWoolson is directed to establishing a reference plane through which theacetabulum can be reamed and generally prepared to receive theacetabular cup implant. The method provides for establishing thereference plane based on selecting three reference points, preferablythe 12 o'clock position on the superior rim of the acetabulum and twoother reference points, such as a point in the posterior rim and theinner wall, which are known distances from the superior rim. Thelocation of the superior rim is determined by performing a series ofcomputed tomography (CT) scans that are concentrated near the superiorrim and other reference locations in the acetabular region.

In the Woolson method, calculations are then performed to determine aplane in which the rim of the acetabular cup should be positioned toallow for a predetermined rotation of the femoral head in the cup. Thedistances between the points and the plane are calculated and anorientation jig is calibrated to define the plane when the jig ismounted on the reference points. During the surgical procedure, thesurgeon must identify the 12 o'clock orientation of the superior rim andthe reference points. In the preferred mode, the jig is fixed to theacetabulum by drilling a hole through the reference point on the innerwall of the acetabulum and affixing the jig to the acetabulum. The jigincorporates a drill guide to provide for reaming of the acetabulum inthe selected plane.

A number of difficulties exist with the Woolson method. For example, thepreferred method requires drilling a hole in the acetabulum. Also,visual recognition of the reference points must be required andprecision placement of the jig on reference points is performed in asurgical setting. In addition, proper alignment of the reaming devicedoes not ensure that the implant will be properly positioned, therebyestablishing a more lengthy and costly procedure with no guarantee ofbetter results. These problems may be a reason why the Woolson methodhas not gained widespread acceptance in the medical community.

In U.S. Pat. Nos. 5,251,127 and 5,305,203 issued to Raab, acomputer-aided surgery apparatus is disclosed in which a reference jigis attached to a double self indexing screw, previously attached to thepatient, to provide for a more consistent alignment of the cuttinginstruments similar to that of Woolson. However, unlike Woolson, Raab etal. employ a digitizer and a computer to determine and relate theorientation of the reference jig and the patient during surgery with theskeletal shapes determined by tomography.

Similarly, U.S. Pat. Nos. 5,086,401, 5,299,288 and 5,408,409 issued toGlassman et al. disclose an image directed surgical robotic system forreaming a human femur to accept a femoral stem and head implant using arobot cutter system. In the system, at least three locating pins areinserted in the femur and CT scans of the femur in the region containingthe locating pins are performed. During the implanting procedure, thelocating pins are identified on the patient, as discussed in col. 9,lines 19-68 of Glassman's '401 patent. The location of the pins duringthe surgery are used by a computer to transform CT scan coordinates intothe robot cutter coordinates, which are used to guide the robot cutterduring reaming operations.

While the Woolson, Raab and Glassman patents provide methods andapparatuses that further offer the potential for increased accuracy andconsistency in the preparation of the acetabular region to receiveimplant components, none of these references provide minimally invasiveassistance during the implant procedure.

In addition, both the Raab and Glassman methods and apparatuses requirethat fiducial markers be attached to the patient prior to performingtomography of the patients. Following the tomography, the markers musteither remain attached to the patient until the surgical procedure isperformed or the markers must be reattached at the precise locations toallow the transformation of the tomographic data to the roboticcoordinate system, either of which is undesirable and/or difficult inpractice.

Thus, in addition to a continued need to provide improved systems andmethods to provide proper placement plans and joint preparationtechniques to ensure optimal outcomes in terms of range of motion andusage, there exists a need for improved intra-operative implantplacement systems and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are illustrated by way of example and not limitation inthe figures of the accompanying drawings in which:

FIG. 1 is a block diagram depicting a system for providing navigationand control to an implant positioning device, according to an exampleembodiment.

FIG. 2 is a diagram illustrating an environment for operating a systemfor navigation and control of an implant positioning device, accordingto an example embodiment.

FIG. 3 is a flowchart illustrating a method for navigation and controlof an implant positioning device, according to an example embodiment.

FIG. 4 is a flowchart illustrating a method for establishing a threedimensional coordinate system, according to an example embodiment.

FIG. 5 is a flowchart illustrating a method for generating controlsignals to control an implant positioning device, according to anexample embodiment.

FIG. 6 is a flowchart illustrating a method for providing assistance toa surgeon operating an implant positioning device, according to anexample embodiment.

FIG. 7 is a diagram illustrating an implant positioning device,according to an example embodiment.

FIGS. 8A-8B are block diagrams illustrating an alternative end effectorfor the implant positioning device, according to an example embodiment.

FIG. 9 is a block diagram illustrating another alternative arrangementfor circumferential actuators, according to an example embodiment.

FIGS. 10A-10B are block diagrams illustrating an articulating portion ofthe powered impactor, according to an example embodiment.

FIG. 11 is a diagrammatic representation of a machine in the exampleform of a computer system within which a set of instructions for causingthe machine to perform any one or more of the methodologies discussedherein may be executed.

DEFINITIONS

Implant—For the purposes of this specification and the associatedclaims, the term “implant” is used to refer to a prosthetic device orstructure manufactured to replace or enhance a biological structure. Forexample, in a total hip replacement procedure a prosthetic acetabularcup (implant) is used to replace or enhance a patients worn or damagedacetabulum. While the term “implant” is generally considered to denote aman-made structure (as contrasted with a transplant), for the purposesof this specification an implant can include a biological tissue ormaterial transplanted to replace or enhance a biological structure.

Implant host—For the purposes of this specification and the associatedclaims, the term “implant host” is used to refer to a patient. Incertain instances the term implant host may also be used to refer, morespecifically, to a particular joint or location of the intended implantwithin a particular patient's anatomy. For example, in a total hipreplacement procedure the implant host may refer to the hip joint of thepatient being replaced or repaired.

Real-time—For the purposes of this specification and the associatedclaims, the term “real-time” is used to refer to calculations oroperations performed on-the-fly as events occur or input is received bythe operable system. However, the use of the term “real-time” is notintended to preclude operations that cause some latency between inputand response, so long as the latency is an unintended consequenceinduced by the performance characteristics of the machine.

DETAILED DESCRIPTION

Example systems and methods for providing and using a navigated andcomputer controlled implant positioning device are described. In someexample embodiments, the systems and methods for computer-aidednavigation and control of an implant positioning device can involve acomputer-controllable powered impactor. In an example, thecomputer-controllable powered impactor can be used by a surgeon toinsert a prosthetic acetabular cup into the acetabulum of an implanthost (e.g., a patient). In other examples, an alternative implantpositioning device can be used to assist in a similar arthroplastyprocedure, such as a total knee replacement. In the followingdescription, for purposes of explanation, numerous specific details areset forth in order to provide a thorough understanding of exampleembodiments. It will be evident, however, to one skilled in the art,that the present invention may be practiced without these specificdetails. It will also be evident that a computer controlled implantpositioning system is not limited to the examples provided and mayinclude other scenarios not specifically discussed.

In an example, the discussed system includes an acetabular positioningdevice outfitted with additional impaction devices. The positioningdevice can be tracked in at least 2 degrees of rotation by a trackingsystem connected to a computer. Programs running on a control system cancommunicate with the tracking system to monitor the orientation andoptionally the position of the acetabular implant as the user orients itrelative to the patient's body (which is also tracked by the trackingsystem) in order to achieve an intended preoperative plan, which isstored in the control system's memory. The control system also caninclude a display that gives the user (e.g., surgeon) informationregarding the current position and/or orientation relative to the bodyposition, and/or relative to the preoperative plan. The control systemcan also communicate with the impaction device(s). A variety ofalgorithms may be used to calculate which and how impact devices shouldbe activated. The simplest algorithm could be that the impact devicesactivate when the user aligns the acetabular implant coincident to thepreoperative plan. Furthermore, this actuation could be dependent onsecondary input from the user, like a trigger, foot pedal signal, orvoice command.

The impaction devices may be mounted to the acetabular positioner suchthat the impactions apply forces or torques to the implant in a knownway, and the computer algorithms may use robotic path planningtechniques to optimize a sequence of impactions to push the acetabularcomponent in an optimized pattern toward the final preoperative plan.

Additional sensors can be deployed on the positioning tool in order togive feedback on forces and torques applied to the positioning tool, orto measure the force and torque applied to a partially or fully fixedacetabular implant by the positioning device, which could affect theresult of the impaction patterns that are employed.

Example System

FIG. 1 is a block diagram depicting a system 100 for providingnavigation and control to an implant positioning device 130, accordingto an example embodiment. In an example, the system 100 can include acontrol system 110, a tracking system 120, and an implant positioningdevice 130. Optionally, the system 100 can also include a display device140 and a database 150. In an example, these components can be combinedto provide navigation and control of the implant positioning device 130during an orthopedic (or similar) prosthetic implant surgery.

The control system 110 can include one or more computing devicesconfigured to coordinate information received from the tracking system120 and provide control to the implant positioning device 130. In anexample, the control system 110 can include a planning module 112, anavigation module 114, a control module 116, and a communicationinterface 118. The planning module 112 can provide pre-operativeplanning services that allow clinicians the ability to virtually plan aprocedure prior to entering the operating room. The background discussesa variety of pre-operative planning procedures used in total hipreplacement (total hip arthroplasty (THA)) that may be used in surgicalrobotic assisted joint replacement procedures. Additionally, U.S. Pat.No. 6,205,411 titled “Computer-assisted Surgery Planner andIntra-Operative Guidance System,” to Digioia et al., discusses yetanother approach to pre-operative planning U.S. Pat. No. 6,205,411 ishereby incorporated by reference in its entirety.

In an example, such as THA, the planning module 112 can be used tomanipulate a virtual model of the implant in reference to a virtualimplant host model. The implant host model can be constructed fromactual scans of the target patient, such as computed tomography (CT),magnetic resonance imaging (MRI), positron emission tomographic (PET),or ultrasound scanning of the joint and surround structure.Alternatively, the pre-operative planning can be performed by selectinga predefined implant host model from a group of models based on patientmeasurements or other clinician selected inputs. In certain examples,pre-operative planning is refined intra-operatively by measuring thepatient's (target implant host's) actual anatomy. In an example, a pointprobe connected to the tracking system 120 can be used to measure thetarget implant host's actual anatomy.

In an example, the navigation module 114 can coordinate tracking thelocation and orientation of the implant, the implant host, and theimplant positioning device 130. In certain examples, the navigationmodule 114 may also coordinate tracking of the virtual models usedduring pre-operative planning within the planning module 112. Trackingthe virtual models can include operations such as alignment of thevirtual models with the implant host through data obtained via thetracking system 120. In these examples, the navigation module 114receives input from the tracking system 120 regarding the physicallocation and orientation of the implant positioning device 130 and animplant host. Tracking of the implant host may include tracking multipleindividual bone structures. For example, during a total knee replacementprocedure the tracking system 120 may individually track the femur andthe tibia using tracking devices anchored to the individual bones.

In an example, the control module 116 can process information providedby the navigation module 114 to generate control signals for controllingthe implant positioning device 130. In certain examples, the controlmodule 116 can also work with the navigation module 114 to producevisual animations to assist the surgeon during an operative procedure.Visual animations can be displayed via a display device, such as displaydevice 140. In an example, the visual animations can include real-time3-D representations of the implant, the implant host, and the implantpositioning device 130, among other things. In certain examples, thevisual animations are color-coded to further assist the surgeon withpositioning and orientation of the implant.

In an example, the communication interface 118 facilitates communicationbetween the control system 110 and external systems and devices. Thecommunication interface 118 can include both wired and wirelesscommunication interfaces, such as Ethernet, IEEE 802.11 wireless, orBluetooth, among others. As illustrated in FIG. 1, in this example, theprimary external systems connected via the communication interface 118include the tracking system 120 and the implant positioning device 130.Although not shown, the database 150 and the display device 140, amongother devices, can also be connected to the control system 110 via thecommunication interface 118. In an example, the communication interface118 communicates over an internal bus to other modules and hardwaresystems within the control system 110.

In an example, the tracking system 120 provides location and orientationinformation for surgical devices and parts of an implant host's anatomyto assist in navigation and control of semi-active robotic surgicaldevices. The tracking system 120 can include a tracker that includes orotherwise provides tracking data based on at least three positions andat least three angles. The tracker can include one or more firsttracking markers associated with the implant host, and one or moresecond markers associated with the surgical device (e.g., an implantpositioning device 130). The markers or some of the markers can be oneor more of infrared sources, Radio Frequency (RF) sources, ultrasoundsources, and/or transmitters. The tracking system 120 can thus be aninfrared tracking system, an optical tracking system, an ultrasoundtracking system, an inertial tracking system, a wired system, and/or aRF tracking system. One illustrative tracking system can be theOPTOTRAK® 3-D motion and position measurement and tracking systemdescribed herein, although those of ordinary skill in the art willrecognize that other tracking systems of other accuracies and/orresolutions can be used.

U.S. Pat. No. 6,757,582, titled “Methods and Systems to Control aShaping Tool,” to Brisson et al., provides additional detail regardingthe use of tracking systems, such as tracking system 120, within asurgical environment. U.S. Pat. No. 6,757,582 (the '582 patent) ishereby incorporated by reference in it's entirely.

In an example, a surgeon can use the implant positioning device 130 toassist in inserting an implant within an implant host during a surgicalprocedure. For example, within THA a surgeon will often insert aprosthetic acetabular cup into the implant host's acetabulum. Insertinga prosthetic acetabular cup often involves a manual or powered impactiondevice. When a manual impactor is used, the surgeon will hammer on theend of the impactor with a mallet to seat the artificial acetabular cup(e.g., implant) into the proper position. While some manual impactiondevices have been coupled with tracking systems, such as tracking system120, the assistance provided to the surgeon is limited to alignment ofthe manual impaction device. The systems currently available lack theability to provide navigated control of an impaction device to assistthe surgeon in getting the implant into the ideal implant location (asdetermined via pre-operative and intra-operative planning) Additionaldetails on an example navigated implant positioning device, such asimplant positioning device 130, are provided below in reference to FIG.7.

Example Operating Environment

FIG. 2 is a diagram illustrating an environment for operating a system200 for navigation and control of an implant positioning device 130,according to an example embodiment. In an example, the system 200 caninclude components similar to those discussed above in reference tosystem 100. For example, the system 200 can include a control system110, a tracking system 120, an implant positioning device 130, and oneor more display devices, such as display device 140A and 140B. Thesystem 200 also illustrates an implant host 10, tracking markers 160,162, and 164, as well as a foot control 170.

In an example, the tracking markers 160, 162, and 164 can be used by thetracking system 120 to track location and orientation of the implanthost 10, the implant positioning device 130, and a reference, such as anoperating table (tracking marker 164). In this example, the trackingsystem 120 uses optical tracking to monitor the location and orientationof tracking markers 160, 162, and 164. Each of the tracking markers 160,162, and 164) includes three or more tracking spheres that provideeasily processed targets to determine location and orientation in up tosix degrees of freedom. The tracking system 120 can be calibrated toprovide a localized 3-D coordinate system within which the implant host10 and the implant positioning device 130 (and by reference the implant)can be spatially tracked. For example, as long as the tracking system120 can image three of the tracking spheres on a tracking marker, suchas tracking marker 160, the tracking system 120 can utilize imageprocessing algorithms to generate points within the 3-D coordinatesystem. Subsequently, the tracking system 120 (or the navigation module114 (FIG. 1) within the control system 110) can use the 3 points totriangulate an accurate 3-D position and orientation associated with thedevice the tracking marker is affixed to, such as the implant host 10 orthe implant positioning device 130. Once the precise location andorientation of the implant positioning device 130 is known, the system200 can use the known properties of the implant positioning device 130to accurately calculate a position and orientation associated with theimplant (without the tracking system 120 being able to visualize theimplant, which may be within the implant host 10 and not visible to thesurgeon or the tracking system 120).

Operations and capabilities of the systems 100 (FIG. 1) and 200 arediscussed further below in reference to FIGS. 3-6.

Example Methods

FIG. 3 is a flowchart illustrating a method 300 for navigation andcontrol of an implant positioning device 130 (FIG. 2), according to anexample embodiment. In an example, the method 300 can include operationsfor: accessing an implant plan at 310, establishing a 3-D coordinatesystem at 320, receiving tracking information at 330, determiningimplant position and orientation at 335, determining if a plannedlocation has been reached at 340, generating control signals at 345, andtransmitting control signals at 350. Optionally, the method 300 can alsoinclude operations such as creating an implant plan at 305, initializinga communication link at 315, and providing feedback to a surgeon at 355.In general, the operations discussed in reference to method 300 areperformed within the control system 100 (FIG. 1). However, in certainexamples, some of the operations may be performed within othercomponents of systems 100 or 200, such as the tracking system 120 (FIG.2). Additionally, in some examples, some of the recited operations maynot be required to provide navigation and control to an implantpositioning device 130 (FIG. 2).

In an example, the method 300 can optionally begin at 305 with theplanning module 112 (FIG. 1) assisting a clinician in creating animplant plan. Creating an implant plan can include generating a virtualimplant host model from CT, MRI, or similar medical scans of theappropriate anatomy of the implant host 10 (FIG. 2). Creating an implantplan can also include manipulation of a virtual implant model inreference to a virtual implant host model. Further, creating an implantplan can include planning bone shaping procedures to be performed priorto implant insertion within the implant host 10. In an example, theimplant plan created in this operation can provide detailed location andorientation data regarding the ideal implant location within an implanthost, such as implant host 10.

At 310, the method 300 can continue with the control system 110 (FIG. 1)accessing an implant plan, such as the implant plan created in operation305. Alternatively, the control system 110 may access an implant planstored in database 150 (FIG. 1). In an example, data regarding theimplant, the desired (ideal) implant location, and the implant host 10within the implant plan can be made available to the navigation module114 and control module 116 as necessary to provide navigation andcontrol to an implant positioning device, such as implant positioningdevice 130 (FIG. 2).

At 315, the method 300 can optionally continue with the control system110, via the communication interface 118, initializing a communicationlink with the implant positioning device 130 and/or the tracking system120 (FIG. 1). Initializing the communication link can, in certainexamples, include verifying control capabilities of the implantpositioning device 130. For example, the systems 100 and 200 (FIGS. 1 &2) may be suitable for use with a computer-controlled powered impactorwith or without extension capabilities, which provides a controllabletelescoping extension for assisting with implant insertion. Initializingthe communication link with the implant positioning device 130 candetermine whether the connected device includes a powered extensioncapability.

At 320, the method 300 can continue with the control system 110establishing a 3-D coordinate system to track the surgical instrumentsand implant host 10 (FIG. 2) during the procedure. In an example, thecontrol system 110 works in conjunction with the tracking system 120(FIG. 2) to establish a localized 3-D coordinate system. In certainexamples, the control system 110 can step a clinician through alignmentand calibration operations involving tracking markers, such as trackingmarkers 160, 162, and 164 (FIG. 2), to establish the 3-D coordinatesystem. Establishing the 3-D coordinate system may also involve use of apoint probe associated with the tracking system 120. Further detailsregarding operation 320 are discussed below in reference to FIG. 4.

At 330, the method 300 can continue with the control system 110receiving tracking information from the tracking system 120 (FIG. 1). Inthis example, at operation 330 the method 300 enters the intra-operativephase. Within the intra-operative phase surgical instruments, theimplant host 10 (FIG. 2), and the implant can be tracked to assist aclinician in performing the surgical procedure. The tracking informationreceived in operation 330 can include location and orientationinformation for components of the systems 100 or 200, such as theimplant host 10 and the implant positioning device 130 (FIGS. 1 & 2). Inother examples, the tracking information received in operation 330 canconsist merely of reference points detected for each tracked component,such as identified locations of the tracking spheres on tracking marker160 (FIG. 2). In these examples, the navigation module 114 (FIG. 1) canuse the reference points to calculate location and orientation dataassociated with the tracked component.

In an example, at 335, the method 300 can continue with the navigationmodule 114 (FIG. 1) determining implant position and orientation. Incertain other examples, determining implant position and orientation maybe done within the tracking system 120 (FIG. 2). In an example, theimplant position and orientation is calculated based on the knownlocation and orientation of the implant positioning device 130 (FIG. 2)and the known relationship between the implant positioning device 130and the implant. For example, the tracking system 120 can provide apoint location and orientation within the 3-D coordinate systemassociated with the implant positioning device 130. Pre-operativecalibration of the implant positioning device 130 can determine therelative position of an end effector of the implant positioning device130, which allows a location and orientation of an implant affixed tothe end effector to be determined. Calibrating this relationship allowsfor the navigation module 114 to track the precise location of theimplant via receiving the tracked location of the implant positioningdevice 130.

At 340, the method 300 can continue with the control system 110determining whether the implant has reached the planned (e.g., ideal)location in reference to the implant host 10 (FIG. 2). If the idealimplant location has been achieved, the method 300 can conclude. If theimplant has not reached the ideal implant location, then at 345 themethod 300 can continue with the control module 116 (FIG. 1) generatingcontrol signals to navigate and control the implant positioning device130 (FIG. 2). Additional detail regarding control signal generation isdiscussed below in reference to FIG. 5.

At 350, the method 300 continues with the control module 116transmitting, over the communication interface 118, the control signalsto the implant positioning device 130 (FIG. 1). The process of receivingtracking information, determining implant location, generating controlsignals, and transmitting the control signals represented by operations330 through 350 can occur as often as every few milliseconds, allowingthe control system 110 (FIG. 2) to rapidly alter the control parameterssent to the implant positioning device 130. Cycles times provided hereinare merely exemplary and may be altered by application of specializedprocessing hardware or optimized algorithms. Additionally, physicalconstraints such as vibration settling time may also affect the timingof control cycles in operation. The ability to rapidly alter the controlparameters allows for accurate control over the placement andorientation of the implant within the implant host 10 (FIG. 2).

At 355, the method can optionally continue with the control system 110(FIG. 2) providing feedback to the surgeon to further assist inpositioning the implant. As discussed in greater detail below inreference to FIG. 6, the feedback provided to the surgeon can be visual,audible, and tactile.

As noted above, the method 300 can loop through operations 330-355 untilit is determined, at operation 340, that the implant has reached theideal location and orientation. In an example, the method 300 can alsobe halted or paused by a clinician during the implant procedure. Ifpaused, the control system 110 (FIG. 2) can allow the clinician tocontinue the implant procedure. If the method 300 is halted, theclinician can be provided options for withdrawing the implant or leavingthe implant in the position reached prior to halting the navigation andcontrol method. In certain examples, the implant positioning device 130(FIG. 2) can include a trigger actuator that can be configured to startand subsequently pause the operations discussed in reference to FIG. 3.

The following methods provide additional detail regarding operationsintroduced above in reference to FIG. 3. The operations discussed in thefollowing methods are optional and may be performed in a different orderor on different systems than those discussed in the following examples.Additionally, the operations discussed above in reference to FIG. 3 maynot all be necessary to provide navigation and control to an implantpositioning device, such as implant positioning device 130 (FIG. 2).Further, the order of operations discussed above is merely exemplary,the discussed operations may be performed in different orders and ondifferent systems than discussed above.

FIG. 4 is a flowchart illustrating a method 320 for establishing a threedimensional (3-D) coordinate system, according to an example embodiment.In an example, the method 320 can include operations such as: systemcalibration at 410, registration of an implant host 10 at 420,registration of an implant positioning device 130 at 430, aligning animplant host model with an implant host 10 at 440, and aligning animplant model with an implant host 10 (FIG. 2) at 450. The method 320corresponds to the operation 320 introduced is FIG. 3. The operationsdiscussed in reference to method 320 represent an example embodiment ofoperation 320.

The method 320 can begin at operation 410 with the control system 110and the tracking system 120 (FIG. 2) performing a system calibration.Calibration of the tracking system 120 enables precise tracking oftracking markers within the field of view of the tracking system 120. Inan example, the tracking system 120 can include a point probe and acalibration fixture for calibrating the tracking system 120. Thetracking system 120, or the control system 110 in conjunction with thetracking system 120, can step a clinician through calibration of a pointprobe using a calibration fixture. The calibration fixture can provideprecise orientation of a 3-D coordinate system and the point probe canthen be used to register (e.g., calibrate) other components to betracked, such as an implant host 10 and an implant positioning device130 (FIG. 2). The tracking system 120, or the control system 110 inconjunction with the tracking system 120, can step a clinician throughcalibration of a point probe optionally using a calibration fixture. Thecalibration process defines precise position and orientation of a 3-Dcoordinate system related to the point probe (especially at its tip).The probe can then be used to register (e.g., calibrate) othercomponents to be tracked, such as an implant host 10 and an implantpositioning device 130.

At 420, the method 320 can continue with the control system 110facilitating registration of the implant host 10 with the trackingsystem 120 (FIG. 2). In an example, a tracking marker, such as trackingmarker 162 (FIG. 2) can be affixed to the implant host 10. With thetracking marker affixed, the clinician can use a calibrated point probeto locate landmarks on the implant host 10 to register the criticalanatomy with the tracking system 120. Registration provides the controlsystem 110 and/or the tracking system 120 the information necessary totranslate the position of the tracking marker 162 into location andorientations relative to the anatomy of the implant host 10 that will beinvolved in the surgical procedure. For example, in THA the registrationprocedure may locate relative locations of the implant host 10'sacetabulum.

At 430, the method 320 can continue with the control system 110 and/ortracking system 120 facilitating registration of the implant positioningdevice 130 within the 3-D coordinate system established by the trackingsystem 120 (FIG. 2). In an example, registration of the implantpositioning device 130 can include using a point probe calibrated to the3-D coordinate system to locate landmark locations on the implantpositioning device 130. Tracking system 120 uses location informationfor the tracking marker 160 (FIG. 2) attached to the implant positioningdevice 130 in conjunction with the landmark points identified by thepoint probe to register the critical dimensions and relative locationson the implant positioning device 130.

At 440, the method 320 can continue with the control system 110 aligninga virtual implant host model with the implant host 10 (FIG. 2). Asdiscussed above, an implant plan can include a virtual implant hostmodel, which can be used for pre-operative planning of implant locationand orientation. In certain examples, the virtual implant host model canbe aligned within the 3-D coordinate system established by the trackingsystem 120 to assist in navigation and control of the implantpositioning device 130 (FIG. 2). Alignment of the virtual implant hostmodel can be done from the landmark locations gathered on the implanthost 10 during registration of the implant host 10. The aligned virtualimplant host model can be used to assist the surgeon in visualizing theimplant location through 3-D visualizations on a display device, such asdisplay device 140 (FIG. 2).

At 450, the method 320 can continue with the control system 110 aligninga virtual implant model with the implant host 10 (FIG. 2). Similar tothe virtual implant host model, the virtual implant model can be usedduring pre-operative planning to identify an ideal location for theimplant within an implant host, such as implant host 10. In order toproperly navigate and control the implant positioning device 130, thevirtual implant model used for planning can be aligned within the 3-Dcoordinate system established by the tracking system 120 (FIG. 2) in theideal location identified during planning. In certain examples, thevirtual implant model can also be used to assist the surgeon invisualizing the implant location during the insertion procedure.

FIG. 5 is a flowchart illustrating a method 345 for generating controlsignals to control an implant positioning device 130 (FIG. 2), accordingto an example embodiment. In an example, the method 345 can includeoperations such as: determining an amplitude of impact at 510,determining a frequency of impact at 520, determining a duration ofimpact at 530, determining extension or retraction parameters at 540,determining orientation parameters at 550, and determining releaseparameters and timing at 560. The control signal generation operationsillustrated in FIG. 5 are directed towards a computer-controlled poweredimpaction device, such as the one described below in reference to FIG.7. In examples using a different type of implant positioning device, adifferent set of control signal generation operations may be applicable.

In this example, the method 345 can begin at 510 with the control module116 (FIG. 1) determining the amplitude of impact based on parameterssuch as current implant location and orientation in reference to theideal implant location. Amplitude of impact is used here to refer to themagnitude of force applied by the implant positioning device 130 (FIG.2) to the implant. At 520, the method 345 can continue with the controlmodule 116 determining a frequency of impact to be sent to the implantpositioning device 130. Frequency of impact is used here to refer to howoften the implant positioning device 130 delivers an impact at theplanned amplitude.

At 530, the method 345 can continue with the control module 116 (FIG. 1)determining duration of the impacts to be delivered with the currentamplitude and frequency parameters. In another example, duration may becalculated to assist the clinician in determining how long a particularorientation of the implant positioning device 130 (FIG. 2) should bemaintained. In certain examples, the control system 110 can utilize apulse-measure-pulse-measure control scheme with varying durationsrelated to the amplitude and frequencies being applied. In yet otherexamples, set impact durations may be used to keep the surgeon engagedin the alignment process and allow time to check progress betweenautonomous motions.

In certain examples, the implant positioning device 130 (FIG. 2) mayinclude the ability to extent and/or retract a portion of the device. Inthese examples, the method 345 may include an operation 540. At 540, themethod 345 can continue with the control module 116 (FIG. 1) determiningextension or retraction parameters to send to the implant positioningdevice 130. For example, during insertion of a prosthetic acetabular cupwith a computer-controlled powered impaction device, the device may bedesigned to allow the clinician to merely maintain a proper alignment,while the device extends an impaction head (e.g., end effector) with theimplant into the proper location.

At 550, the method 345 can continue with the control module 116determining orientation parameters to be sent to the implant positioningdevice 130 (FIG. 1). In certain examples, the implant positioning device130 may have the ability to control orientation of the implant on theend effector. Such as in the example of a prosthetic acetabular cup, theend effector may be configured to allow impacts to be directed tolocalized portions on the circumference of the implant. Localizingimpacts to a small portion of the circumference can induce a rotationforce on the implant. In other examples, the end effector of the implantpositioning device 130 may be able to pivot or rotate to facilitateother orientation adjustments.

Finally, at 560, the method 345 can conclude with the control module 116(FIG. 1) determining release parameters and timing. In an example, theimplant positioning device 130 (FIG. 2) can include a mechanism torelease the implant once it has reached the ideal location. Releaseparameters can include parameters to instruct the implant positioningdevice 130 to release an implant retaining mechanism or trigger arelease actuator to remove the implant from the end effector. In anexample, a release actuator can include a simple air or electricallyactuated cylinder within the end effector to release the implant.

FIG. 6 is a flowchart illustrating a method 350 for providing assistanceto a surgeon operating an implant positioning device 130 (FIG. 2),according to an example embodiment. In an example, the method 350 caninclude operations such as: determining location and orientation of theimplant positioning device 130 at 610, determining alignment andorientation of implant host 10 (FIG. 2) at 615, generating 3-Drepresentations at 620, displaying cross-hair alignment guides at 625,displaying 3-D representations at 630, displaying ideal implant locationat 635, displaying an implant host model at 640, producing audiblealignment indicators at 645, and generating haptic control signals at650. The following operations highlight one of the many potentialbenefits of computer-aided navigation and control, the ability to assista clinician by visualizing aspects of an implant host 10's anatomy andthe implant during a procedure where both may be partially or completelyobstructed from view.

In an example, the method 350 can begin at 610 with the navigationmodule 114 determining location and orientation of the implantpositioning device 130 (FIG. 1). In certain examples, the location andorientation of the implant positioning device 130 will have already beencalculated to determine the location and orientation of the implant (seeoperation 335 in FIG. 3). At 615, the method 350 can continue with thenavigation module 114 determining, if necessary, a location andorientation of the implant host 10 (FIG. 2). Like operation 610,operation 615 may have been performed previously to determine theimplant location relative to the implant host 10.

At 620, the method 350 can continue with the control system 110generating 3-D representations of components such as the implant and theimplant positioning device 130 as well as the implant host 10 (FIG. 2).The representations generated may be used to present real-timevisualizations to the surgeon. At 625, the method 350 can continue withthe control system 110 generating and displaying cross-hair alignmentguides to assist the surgeon in aligning the implant positioning device130. In an example, information including the current implant location,the ideal (planned) implant location, location and orientation of theimplant positioning device 130, and location orientation of the implanthost 10 can be used to generate the cross-hair alignment guides. In anexample, two (2) dimensions (e.g., x and y) on a cross-hair alignmentdisplay can correspond to the azimuth and elevation of the implantpositioning device 130 in a spherical coordinate system aligned to theimplant plan. The center of the XY plot corresponds to the implant plan,and the XY coordinates of the implant positioning device 130 are theazimuth and elevation differences between the implant positioning device130 and implant plan. In certain scenarios, this definition may lead toa non-intuitive correlation between motion of the implant positioningdevice 130 and movement of the cross-hair on the screen. Therefore,angular reference planes may be aligned to global references, such asgravity or the user's facing direction. These references allow for theuser's left to correspond to leftward motion on the screen, and motionin the upward direction (relative to gravity) of the implant positioningdevice 130 handle to upward motion of the cross-hair. Transformations ofthe reference coordinates in this manner are evident to those skilled inthe art of robotics or surgical navigation.

At 625, the method 350 can continue with the control system 110displaying 3-D representations on a display device, such as displaydevice 140 (FIG. 2). In an example, the 3-D representations generated inoperation 620 can be displayed to assist the surgeon in visualizingimplant location and orientation of the implant positioning device 130(FIG. 2), among other things. In some examples, the 3-D visualizationscan be color-coded to provide additional feedback to the surgeon. Forexample, each different component, such as the implant, the implant host10 (FIG. 2), and the implant positioning device 130, can be representedas a different color. In another example, the implant can be color-codedto indicate alignment in reference to the implant host 10. In thisexample, the color-coding can change from red to green (with variousshades in between) to indicate where the implant is or is not properlyaligned. At 635, the method 350 can continue with the control system 110displaying the ideal implant location in reference to the various other3-D representations, such as the implant host 10, the actual implant,and the implant positioning device 130. At 640, the method 350 cancontinue with the control system 110 adding a 3-D visualization of theimplant host model to the display. In an example, the nature of the 3-Dvisualization displayed on the display device 140 can be controlled viafoot control 170 (FIG. 2) by the surgeon. Controlling the display canenable the surgeon to scroll through various perspectives or controlwhich components are displayed at a given time.

At 645, the method 350 can continue with the control system 110 (FIG. 2)generating audible alignment indicators. The audible alignmentindicators can indicate implant alignment or implant positioning device130 (FIG. 2) alignment according to the implant plan. Finally, at 650,the method 350 can conclude with the control system 110 generatinghaptic control signals to transmit to the implant positioning device130. The haptic control signals can instruct the implant positioningdevice 130 to produce a vibration to provide tactile feedback to thesurgeon. In an example, haptic tactile feedback may be used to indicatea particularly bad alignment of the implant positioning device 130relative to the implant plan. Alternatively, haptic tactile feedback canbe used to indicate a successful placement of the implant.

Example Implant Positioning Device

FIG. 7 is a diagram illustrating an implant positioning device 130,according to an example embodiment. In an example, the implantpositioning device 130 can include components such as: a body 705, ahandle 710, a battery 715, a chuck 720, a telescoping positioning arm730, a stabilizing handle 735, an end effector 740, an implant retentiondevice 745, a trigger 750, a tracking marker 760, a manual impactsurface 770, and a communication link 780. The example implantpositioning device 130 illustrated in FIG. 7 is a cordlesscomputer-controlled impactor that can be used in THA procedures. Otherimplant positioning devices designed for other procedures may includesimilar components to those described in this example.

In this example, the primary components of the implant positioningdevice 130 include a main body 705, a handle 710, a battery (e.g., powersupply) 715, a chuck 720, and a trigger 750. The main body 705 containsa motor and other control circuitry required to produce the desiredimpacts on the end effector 740. The chuck 720 can be configured toallow for inter-changeable positioning arms, such as telescopingpositioning arm 730. In certain examples, the trigger 750 provides amanual override allowing the clinician to control the implantationprocess even while the implant positioning device 130 is receivingcontrol signals from the control system 110.

In this example, the implant positioning device 130 includes atelescoping positioning arm 730. The telescoping positioning arm 730includes a proximal fixed portion 732 and a distal moveable portion 734.In some examples, a stabilizing handle 735 can be affixed to theproximal fixed portion 732 of the telescoping positioning arm 730. Thedistal moveable portion 734 includes an end effector 740 affixed to thedistal end. The end effector 740 can be configured to mate with animplant to reduce any potential damage to the implant during insertion.The end effector 740 can include a retention device 745 that can beconfigured to retain the implant in a fixed position relative to the endeffector 740 during insertion.

The implant positioning device 130 can include a tracking marker 760that allows the location and orientation of the implant positioningdevice 130 to be tracked by the tracking system 120 (FIG. 2). In anexample, the tracking marker 760 can include three or more trackingspheres 765A . . . 765N (collectively referred to as tracking sphere 765or tracking spheres 765). The tracking spheres 765 can be active orpassive devices. For example, active tracking spheres can includeinfrared LEDs enabling a tracking system, such as the commerciallyavailable OPTOTRAK® 3-D motion and position measurement and trackingsystem to track the implant positioning device 130 using infraredsensors. Other tracking systems may use cameras responsive to otherwavelengths, which would indicate the use of tracking spheres emittingcompatible wavelengths (or which reflect light in compatiblewavelengths).

In this example, the implant positioning device 130 can include a manualimpact surface 770. The manual impact surface 770 enables a surgeon torevert to manual impaction in situations where the computer-aidednavigation and control is not functioning properly.

Finally, the implant positioning device 130 can include a communicationlink 780. In this example, the communication link 780 is illustrated asa wired connection. However, in other examples, the communication link780 can be implemented over any suitable wireless protocol, such as IEEE802.11 or Bluetooth, among others.

FIGS. 8A-8B are block diagrams illustrating an alternative end effector800 for the implant positioning device 130, according to an exampleembodiment. The alternative end effector 800 can include a series ofactuators 815A-815C (collectively referred to as actuators 815)positioned between the distal moveable portion 734 and the end effector740. The actuators 815 can induce forces (e.g., impacts) on localizedportions along the outer circumference of the end effector 740. Asdiscussed above, actuators position to direct forces around thecircumference of the end effector 740 can induce a desired rotation onthe implant during impaction. FIG. 8B illustrates a section view of howactuators 815 can be arranged around end effector 740.

FIG. 9 is a block diagram illustrating another alternative arrangementfor circumferential actuators 915A-915C, according to an exampleembodiment. In this example, the circumferential actuators 915A-915C arearranged between the distal moveable portion 734 and the proximal fixedportion 732.

FIGS. 10A-10B are block diagrams illustrating an articulating portion ofthe powered impactor, according to an example embodiment. In thisexample, a portion of the telescoping positioning arm 730 can include anarticulating joint 905. The illustrated example includes thearticulating joint within the distal moveable portion 734 of thetelescoping positioning arm 730. In another example, the articulatingjoint 905 can be included within the proximal fixed portion 732 of thetelescoping positioning arm 730. The articulation joint 905 can bepowered or manually manipulated to assist in positioning the implantduring surgery.

Modules, Components and Logic

Certain embodiments of the computer systems described herein may includelogic or a number of components, modules, or mechanisms. Modules mayconstitute either software modules (e.g., code embodied on amachine-readable medium or in a transmission signal) or hardwaremodules. A hardware module is a tangible unit capable of performingcertain operations and may be configured or arranged in a certainmanner. In example embodiments, one or more computer systems (e.g., astandalone, client or server computer system) or one or more hardwaremodules of a computer system (e.g., a processor or a group ofprocessors) may be configured by software (e.g., an application orapplication portion) as a hardware module that operates to performcertain operations as described herein.

In various embodiments, a hardware module may be implementedmechanically or electronically. For example, a hardware module maycomprise dedicated circuitry or logic that is permanently configured(e.g., as a special-purpose processor, such as a field programmable gatearray (FPGA) or an application-specific integrated circuit (ASIC)) toperform certain operations. A hardware module may also compriseprogrammable logic or circuitry (e.g., as encompassed within ageneral-purpose processor or other programmable processor) that istemporarily configured by software to perform certain operations. Itwill be appreciated that the decision to implement a hardware modulemechanically, in dedicated and permanently configured circuitry, or intemporarily configured circuitry (e.g., configured by software) may bedriven by cost and time considerations.

Accordingly, the term “hardware module” should be understood toencompass a tangible entity, be that an entity that is physicallyconstructed, permanently configured (e.g., hardwired) or temporarilyconfigured (e.g., programmed) to operate in a certain manner and/or toperform certain operations described herein. Considering embodiments inwhich hardware modules are temporarily configured (e.g., programmed),each of the hardware modules need not be configured or instantiated atany one instance in time. For example, where the hardware modulescomprise a general-purpose processor configured using software, thegeneral-purpose processor may be configured as respective differenthardware modules at different times. Software may accordingly configurea processor, for example, to constitute a particular hardware module atone instance of time and to constitute a different hardware module at adifferent instance of time.

Hardware modules can provide information to, and receive informationfrom, other hardware modules. Accordingly, the described hardwaremodules may be regarded as being communicatively coupled. Where multiplesuch hardware modules exist contemporaneously, communications may beachieved through signal transmission (e.g., over appropriate circuitsand buses) that connect the hardware modules. In embodiments in whichmultiple hardware modules are configured or instantiated at differenttimes, communications between such hardware modules may be achieved, forexample, through the storage and retrieval of information in memorystructures to which the multiple hardware modules have access. Forexample, one hardware module may perform an operation and store theoutput of that operation in a memory device to which it iscommunicatively coupled. A further hardware module may then, at a latertime, access the memory device to retrieve and process the storedoutput. Hardware modules may also initiate communications with input oroutput devices, and can operate on a resource (e.g., a collection ofinformation).

The various operations of example methods described herein may beperformed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors may constitute processor-implemented modulesthat operate to perform one or more operations or functions. The modulesreferred to herein may, in some example embodiments, compriseprocessor-implemented modules.

Similarly, the methods described herein may be at least partiallyprocessor-implemented. For example, at least some of the operations of amethod may be performed by one or processors or processor-implementedmodules. The performance of certain of the operations may be distributedamong the one or more processors, not only residing within a singlemachine, but deployed across a number of machines. In some exampleembodiments, the processor or processors may be located in a singlelocation (e.g., within a home environment, an office environment or as aserver farm), while in other embodiments the processors may bedistributed across a number of locations.

The one or more processors may also operate to support performance ofthe relevant operations in a “cloud computing” environment or as a“software as a service” (SaaS). For example, at least some of theoperations may be performed by a group of computers (as examples ofmachines including processors), with these operations being accessiblevia a network (e.g., the Internet) and via one or more appropriateinterfaces (e.g., APIs).

Electronic Apparatus and System

Example embodiments may be implemented in digital electronic circuitry,or in computer hardware, firmware, software, or in combinations of them.Example embodiments may be implemented using a computer program product,for example, a computer program tangibly embodied in an informationcarrier, for example, in a machine-readable medium for execution by, orto control the operation of, data processing apparatus, for example, aprogrammable processor, a computer, or multiple computers. Certainexample embodiments of an implant positioning device 130 (FIG. 7) caninclude a machine-readable medium storing executable instructions to beperformed by the implant positioning device 130.

A computer program can be written in any form of programming language,including compiled or interpreted languages, and it can be deployed inany form, including as a stand-alone program or as a module, subroutine,or other unit suitable for use in a computing environment. A computerprogram can be deployed to be executed on one computer or on multiplecomputers at one site or distributed across multiple sites andinterconnected by a communication network.

In example embodiments, operations may be performed by one or moreprogrammable processors executing a computer program to performfunctions by operating on input data and generating output. Methodoperations can also be performed by, and apparatus of exampleembodiments may be implemented as, special purpose logic circuitry(e.g., a FPGA or an ASIC).

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other. Inembodiments deploying a programmable computing system, it will beappreciated that both hardware and software architectures requireconsideration. Specifically, it will be appreciated that the choice ofwhether to implement certain functionality in permanently configuredhardware (e.g., an ASIC), in temporarily configured hardware (e.g., acombination of software and a programmable processor), or a combinationof permanently and temporarily configured hardware may be a designchoice. Below are set out hardware (e.g., machine) and softwarearchitectures that may be deployed, in various example embodiments.

Example Machine Architecture and Machine-Readable Medium

FIG. 11 is a block diagram of machine in the example form of a computersystem 1100 within which instructions, for causing the machine toperform any one or more of the methodologies discussed herein, may beexecuted. In alternative embodiments, the machine operates as astandalone device or may be connected (e.g., networked) to othermachines. In a networked deployment, the machine may operate in thecapacity of a server or a client machine in server-client networkenvironment, or as a peer machine in a peer-to-peer (or distributed)network environment. The machine may be a personal computer (PC), atablet PC, a set-top box (STB), a PDA, a cellular telephone, a webappliance, a network router, switch or bridge, or any machine capable ofexecuting instructions (sequential or otherwise) that specify actions tobe taken by that machine. Further, while only a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein.

The example computer system 1100 includes a processor 1102 (e.g., acentral processing unit (CPU), a graphics processing unit (GPU) orboth), a main memory 1104 and a static memory 1106, which communicatewith each other via a bus 1108. The computer system 1100 may furtherinclude a video display unit 1110 (e.g., a liquid crystal display (LCD)or a cathode ray tube (CRT)). The computer system 1100 also includes analphanumeric input device 1112 (e.g., a keyboard), a user interface (UI)navigation device (or cursor control device) 1114 (e.g., a mouse), adisk drive unit 1116, a signal generation device 1118 (e.g., a speaker)and a network interface device 1120.

Machine-Readable Medium

The disk drive unit 1116 includes a machine-readable medium 1122 onwhich is stored one or more sets of instructions and data structures(e.g., software) 1124 embodying or used by any one or more of themethodologies or functions described herein. The instructions 1124 mayalso reside, completely or at least partially, within the main memory1104, static memory 1106, and/or within the processor 1102 duringexecution thereof by the computer system 1100, the main memory 1104 andthe processor 1102 also constituting machine-readable media.

While the machine-readable medium 1122 is shown in an example embodimentto be a single medium, the term “machine-readable medium” may include asingle medium or multiple media (e.g., a centralized or distributeddatabase, and/or associated caches and servers) that store the one ormore instructions or data structures. The term “machine-readable medium”shall also be taken to include any tangible medium that is capable ofstoring, encoding or carrying instructions for execution by the machineand that cause the machine to perform any one or more of themethodologies of the present invention, or that is capable of storing,encoding or carrying data structures used by or associated with suchinstructions. The term “machine-readable medium” shall accordingly betaken to include, but not be limited to, solid-state memories, andoptical and magnetic media. Specific examples of machine-readable mediainclude non-volatile memory, including by way of example, semiconductormemory devices (e.g., erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM)) and flashmemory devices; magnetic disks such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks. A“machine-readable storage medium” shall also include devices that may beinterpreted as transitory, such as register memory, processor cache, andRAM, among others. The definitions provided herein of machine-readablemedium and machine-readable storage medium are applicable even if themachine-readable medium is further characterized as being“non-transitory.” For example, any addition of “non-transitory,” such asnon-transitory machine-readable storage medium, is intended to continueto encompass register memory, processor cache and RAM, among othermemory devices.

Transmission Medium

The instructions 1124 may further be transmitted or received over acommunications network 1126 using a transmission medium. Theinstructions 1124 may be transmitted using the network interface device1120 and any one of a number of well-known transfer protocols (e.g.,HTTP). Examples of communication networks include a LAN, a WAN, theInternet, mobile telephone networks, plain old telephone (POTS)networks, and wireless data networks (e.g., WiFi and WiMax networks).The term “transmission medium” shall be taken to include any intangiblemedium that is capable of storing, encoding or carrying instructions forexecution by the machine, and includes digital or analog communicationssignals or other intangible media to facilitate communication of suchsoftware.

Thus, methods and systems for navigation and control of an implantpositioning device have been described. Although the present inventionhas been described with reference to specific example embodiments, itwill be evident that various modifications and changes may be made tothese embodiments without departing from the broader spirit and scope ofthe invention. Accordingly, the specification and drawings are to beregarded in an illustrative rather than a restrictive sense.

Although an embodiment has been described with reference to specificexample embodiments, it will be evident that various modifications andchanges may be made to these embodiments without departing from thebroader spirit and scope of the invention. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense. The accompanying drawings that form a parthereof, show by way of illustration, and not of limitation, specificembodiments in which the subject matter may be practiced. Theembodiments illustrated are described in sufficient detail to enablethose skilled in the art to practice the teachings disclosed herein.Other embodiments may be used and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. This Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments orexamples have been illustrated and described herein, it should beappreciated that any arrangement calculated to achieve the same purposemay be substituted for the specific embodiments shown. This disclosureis intended to cover any and all adaptations or variations of variousembodiments. Combinations of the above embodiments, and otherembodiments not specifically described herein, will be apparent to thoseof skill in the art upon reviewing the above description.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended; that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” “third,” and so forth are used merely as labels, andare not intended to impose numerical requirements on their objects.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

The claimed invention includes:
 1. A method comprising: accessing animplant plan, the implant plan including location and orientation datadescribing an ideal implant location and orientation in reference to animplant host; establishing a three dimensional (3-D) coordinate systemassociated with an implant positioning device and the implant host;receiving tracking information identifying a current implant positioningdevice position and a current implant host position within the 3-Dcoordinate system; generating control signals based on the trackinginformation and the implant plan; and sending the control signals over acommunication link with the implant positioning device, the controlsignals controlling operation of the implant positioning device toassist a surgeon in positioning an implant according to the implantplan, the implant removably coupled to an end effector of the implantpositioning device.
 2. The method of claim 1, wherein the generatingcontrol signals includes generating a signal to control an amplitude ofimpact delivered by the implant positioning device.
 3. The method ofclaim 1, wherein the generating control signals includes generating asignal to control a frequency of impacts delivered by the implantpositioning device.
 4. The method of claim 1, wherein the generatingcontrol signals includes generating a signal to control an extendableelement within the implant positioning device.
 5. The method of claim 1,wherein the generating control signals includes generating a signal todirect positioning impacts delivered by the implant positioning device,wherein the positioning impacts induce a rotation along a particularaxis of the implant.
 6. The method of claim 1, further comprisingpresenting an interface providing feedback assisting the surgeon inaligning the implant with the implant host.
 7. The method of claim 6,wherein the presenting the interface includes presenting a 3-D imageillustrating the implant host, the implant positioning device and theimplant, the 3-D image providing real-time feedback assisting thesurgeon in aligning the implant with the implant host.
 8. The method ofclaim 7, wherein the presenting the 3-D image includes color-codingindicative of a position of the implant relative to the implant host andthe ideal implant location and orientation.
 9. The method of claim 6,wherein the presenting the interface includes presenting cross-hairalignment guides associated with an illustration of the implantpositioning device.
 10. The method of claim 1, wherein the accessing theimplant plan includes extracting an implant model and a implant hostmodel; and wherein the establishing the 3-D coordinate system includesaligning the implant host model and the implant model with the implanthost.
 11. A system comprising: an implant positioning device including atracking component, a communication link for receiving control signals,and an end effector for removably coupling to an implant component; atracking system including a tracking sensor, the tracking systemmonitoring, in real-time, three dimensional position and orientation ofthe implant positioning device and an implant host; a control system,the control system including: a communication interface coupled to theimplant positioning device via the communication link and the trackingsystem, the communication interface sending control signals to theimplant positioning device and receiving tracking informationidentifying a current implant positioning device position and a currentimplant host position; one or more processors coupled to a memorydevice, the memory device including instructions that, when executed bythe one or more processors, cause the control system to generate controlsignals based on the tracking information and an implant plan, thecontrol signals controlling operation of the implant positioning deviceto assist a surgeon in positioning an implant according to the implantplan.
 12. The system of claim 11, wherein the implant positioning deviceis a computer-controlled powered impactor including a communication linkto receive parameters for controlling impaction forces imparted to animplant attached to an end effector of the implant positioning device.13. The system of claim 12, wherein the implant positioning deviceincludes an extendable element attached to the end effector, theextendable element controlling a relative position of the end effectorin reference to the surgeon.
 14. The system of claim 13, wherein thecommunication link of the implant positioning device receives controlsignals including parameters to control impact amplitude, impactfrequency, and end effector position.
 15. The system of claim 11,further comprising a display device communicatively coupled to thecontrol system, the display device presenting an interface providingfeedback assisting the surgeon in aligning the implant with the implanthost.
 16. The system of claim 15, wherein the display device presents a3-D animation illustrating the implant host, the implant positioningdevice, and the implant, the 3-D animation providing real-time feedbackassisting the surgeon in aligning the implant with the implant host. 17.A machine-readable storage medium including instructions that, whenexecuted by a machine, cause the machine to: access an implant plan, theimplant plan including location and orientation data describing an idealimplant location and orientation in reference to an implant host;establish a three dimensional (3-D) coordinate system associated with animplant positioning device and the implant host; receive trackinginformation identifying a current implant positioning device positionand a current implant host position within the 3-D coordinate system;generate control signals based on the tracking information and theimplant plan; and transmit the control signals over a communication linkwith the implant positioning device, the control signals controllingoperation of the implant positioning device to assist a surgeon inpositioning the implant according to the implant plan, the implantremovably coupled to an end effector of the implant positioning device.18. The machine-readable storage medium of claim 17, wherein theinstructions to generate control signals include additional instructionsto generate signals to control amplitude and frequency of impactsdelivered by the implant positioning device.
 19. The machine-readablestorage medium of claim 18, wherein the instructions to generate controlsignals include additional instructions to generate signals to controlan extendable end effector on the implant positioning device.
 20. Themachine-readable storage medium of claim 17, further includinginstructions that cause the machine to generate a three dimensional(3-D) representation illustrating the implant host, the implantpositioning device, and the implant, the 3-D representation providingreal-time feedback to assist the surgeon in aligning the implant withthe implant host.